The invention relates to an elevator monitoring system in general and, in particular, to a system for the central management, regional inspection and local monitoring of decentralized elevator installations.
From U.S. Pat. No. 3,973,648, a system is known which, by way of modem connection, monitors elevator groups by means of a central computer. An elevator group selected by the central computer sends data concerning operational, fault and alarm events in serial digital form to the central computer. A hardware interface with monitoring and transmission functions serves as a connecting member between the elevator group and the central computer.
The disadvantage of this prior art system lies in that the data is passed on unevaluated. The central computer must evaluate the incoming data and decide whether a service action is indicated by reason of the evaluation. The transmission of all actual installation data to the central computer requires a long occupation of rented telephone lines and demands much computer time. A further disadvantage of this system lies in that the central computer calls up the elevator groups to be monitored. Thereby, the relevant installation data is detected not when it arises, but with a delay caused by the interrogation cycle. Beyond that, inquiries occur, at least in the case of small traffic frequencies, when no substantial changes concerning installation data are present.
From U.S. Pat. No. 4,512,442, a system is known which comprises means for the remote monitoring of elevator systems. The data points of an elevator system, which are to be monitored, are connected to an auxiliary computer subordinate to a main computer. For each elevator group, an intelligent, in situ main computer receives the data of the auxiliary computer as well as the data of the elevator group control. This data is prepared by the main computer and passed by way of a modem connection to the central computer. The central computer compiles upkeep lists from the received data and transmits the lists to the responsible service point.
The disadvantage of this prior art system lies in that all data of an elevator group is prepared and transmitted by means of a main computer. In the case of a fault or in the case of a service requirement (maintenance of the software and so forth) of the main computer, the remote monitoring of the entire elevator group fails. A further disadvantage of the known equipment lies in that a modem connection to the central computer is necessary for each main computer. In buildings with several elevator groups, several communication lines to the main computers placed in the machine room must therefore be installed and rented.
From U.S. Pat. No. 4,568,909, a system is known which comprises means for the local and central remote monitoring of elevator systems. For each building, a main computer by means of auxiliary units detects the data of several elevator systems. The main computer evaluates the data and decides whether new operational, fault and alarm events are present. It transmits the events by way of a modem connection to a local service point. Several service points are connected to one superordinate central computer.
The disadvantage of this system lies in that the computer intelligence for an entire building is concentrated in a main computer. Only the combination of auxiliary units with the main computer results in a functionally capable monitoring system. Such a monitoring system has proven to have little flexibility for being expanded, is complicated in terms of hardware and software and is expensive in terms of costs.